Typewriting machine



2 Sheets-Sheet) R. G. THOMPSON TYPEWRITING MACHINE Filed July 6, 1938 2 Sheets-Sheet 2 lNVENTo RUSSELL G. THOMPSON 7W K ATTORNEY v Patented Nov. 26, 1940 UNITED 4STATES PATENT OFFICE TYPEWRITING MACHINE Application July 6, 1938, Serial No. 217,705

2 Claims.

This invention relates to -typewriting machines and with regard to certain more specific features thereof to power-driven type actions.

The invention has for one of its objects to 5 provide a power-driven type action which shall be simple in construction, inexpensive, easy tc assemble and highly eiiicient in operation.

Another object of the invention is to employ a single lobe cam in the power-drive for the l actuation oi the type bar, thus reducing the number of delicate latch parts previously included in the complex double lobe cam power drives of p rior structures, and generally rendering the machine more durable and more certain in l the performance of its intended functions.

It is a furtlier object of the invention to provide transmission connections from the powerdriven actuator to the type bar, which are particularly well adapted to translate the short,

l) substantially uniform, movement of the powerdriven actuator into a forceful initial movement of the type bar from its -inert position and quickly accelerate the type bar in its movement to the platen, wherefrom it returns quickla ly from typing or impact position to a point Well out of the way oi any type bars subsequently operated and thence gradually assumes a position of rest from which there is a minimum of rebound.

$0 Other objects will be in part obvious and in part particularly pointed out as the following description of a preferred embodiment of the invention proceeds.

In the accompanying drawings: y $5 Fig. 1 is a -view in section taken fore and aft of a typewri-ting machine, with frame and carrlage parts indicated schematically.

Fig. 2 is a sectional view showing one of the key-controlled power units. Fig. 3 is a view in elevation of the power unit shown in Fig. 2.

Referring now more particularly to the drawings, a frame is indicated at I0. A carriage Il is mounted -thereon and has a conventional cy- 4| lindrical platen I2. To accommodate the present power unit the frame l0 is provided with cross bars l! and Il suitably comb-slotted to receive and guide a multiplicity of actuating levers and sub-levers which later will be de- I0 scribed in detail. 'I'he frame is provided at its forward end with upper and lower cross bars l5 and It respectively which are rubber-faced as indicated at I1 to contact the forward ends Il oi a multiplicity of key levers I9 which have il their rear ends pivoted at2l on a rod extending .from one side frame to the other. The key levers I9 are provided with keys 2 I.

The power-drive in the embodiment shown is a rubber-covered roller 22 driven by an electric motor (not shown). It will be obvious. however, that the invention, in certain of its aspects, contemplates the use of other power drives such, for example, as the toothed roller and pawl drive disclosed in my copending application Serial No. 149,343, filed June 21, 1937. In other aspects, however, the particular rubber roll power drive herein shown is speciflcally involved in the present type action invention.

The rubber-covered roller 22 is suitably journaled in the machine frame and is preferably continuously rotated in the direction of the arrow in Fig. l. The devices actuated by the rubber roller 22 are in the form of bell crank levers or rockers 23 and 24 pivotally mounted in rows on the cross bars I3 and I4 on pivot rods 20 25 and 26. Each of the bell crank levers is loosely positioned in a slot'in its respective cross bar so as to be guided in its pivotal movement and a stop or series of stops 21 is related to the cross bars to determine the normal positions of 25 the bell crank levers or actuators 23 and 24. The stops 21 are preferably of rubber or some sounddeadening material.

Each of the bell crank levers 23-24 has at its lower end a cam mounted for rotation 30 on a pin 3| extending laterally from the lever. When the bell crank levers are in position against the stops 21 the cams are held slightly out of engagement with the drive roll, as shown in Fig. 2 of the drawings. When any key lever 35 is depressed against the action of its return spring 32 its corresponding or related cam 30 engages the drive roller and is turned thereby the major part of a complete revolution. The mechanism for carrying out this action will now o be described,

'Ihe cam 30, commencing at a low portion normally occupying a position adjacent the lsurface of the drive roller, is serrated as indicated at 33 around its periphery as it gradually builds up to a high point 34. The cam is held with its low point opposite the drive roller by a' latch member 35 pivoted on a stud 36 which projects' laterally from the lower arm of the bell crank lever. This latch is operatively associated with 80 a cam control finger 31 which acts upon a pin 38 extending laterally from the cam 30.

A spring 40 is coiled around .the stud il and hasy one end fixed to a lug 4| which is integral with the cam control linger 31, and itsv other BI the latch 35. The spring tends to urge the latch and the cam control nger toward each other. The lug 42 of latch 35, when in its normal latohing position, is directly under a lip 43 of a latch-operating member 44 pivoted on the key lever at dt and held by a spring v46 against one or the other of the cross bars I3 or I4 asv the case may be. The latch-operating members play in slots at the inner sides of the bars and their normal positions are determined by the inner ends of the slots and the springs 46 each of which has one end xed to the latch-operating member and the other end xed to a lug on an associated key lever. f

When a key lever is depressed itslatch-operating member is moved downwardly against lug d2 which rotates the latch 35 out of engagement with a pin 5I) extending laterally from the cam l0. Thispin is on the opposite side of the cam from the pin 3B and as the cam is released for rotation by movement ofthe latch spring 4l! acting on pin 38 gives the cam a short initial rotation which turns a higher portion of the serrated cam edge into engagement with the continuously rotating power-drive roller which thereupon picks up the cam frictionally and rotates it until its extreme high point 3d passes beyond the roller. During the latter part oi. this action the pin 38 acting upon the latch control finger is vstressing spring d to restore latch 35 to a position where it-will intercept pin 50 when the rotation of the cam is complete. After the high point 36 of the cam has passed fromy the influence of the drive roller the spring-pressed latch control iinger 31 acts upon pin 33 extending from the cam 30 to complete the rotation and reengage pin 50 with the latch 35. The operation just described causes a short o pivotal movement of the associated bell crank lever or actuator which is transmitted to the type bar in a manner now to be described.

For convenience of arrangement and assembly the actuator bell crank levers are arranged in two rows'on opposite sides of the drive roller on the cross bars I3 and Iii. I'he transmission connections, from the actuating levers 23 and 24 are all arranged in spaced slots in the cross bar I4. These consist of sub-levers l of bell crank shape pivoted on rod 26 and having their lower arms 52 yoked at theend around pins 53 extending laterally from the upper arms of actuator levers 23 and 2e. The upper arms of the sub-levers 52 have a link connection 54 with short arms 55 of 55 type bar levers 5B which latter are pivoted on the usual fulcrum wire 5l of a conventional type bar segment (not shown). Return springs 58 extending from the sub-levers to a part xed to the frame tend to maintain the pivot points of links M and pivot rod 26 in alignment, thus effecting a straightened toggle for each type action. Each link 56 has a tail G adapted to strike against a lugSI extending from the upper arm of sub-lever 5I to prevent the toggle from passing over dead center under the influence of spring 58.

As any one of the actuator levers 28 or 24 is moved by the engagement of its associated cam with'the drive roller, its related sub-lever 5I is moved pivotallyto throw its upper arm forwardly to break the toggle and moverthe type bar 56 around its pivot point 5T. It will be obvious that as the toggle is breaking from its straightened position there will result an initial application of considerable force to overcome the inertia of the K 2,223,235 end .is xed in a lug 42 which is integral withV parts and this will be followed by progressive acprinting point. The reverse of this action will take place on the return of the type bar under the inuence of spring 58 and accordingly the type bars in their nnal return movement will settle easily to rest against a support. not shown in the drawings, and be substantially locked against rebound by the straightening of the toggle consisting of the upper arm of sub-lever 5I and link 54.

As the drive roller 22 rotates cam 30 the corresponding actuator lever has its lower arm moved outwardly to disengage' lug 42 from the' latch-operating member 44 and when so disengaged, spring All, as previously stated, acts to bias latch 35 back into latching relation with the cam 30. This, of course, lifts lug 42 slightly so that there can be no subsequent unlatching of the cam until the depressed key lever I9 has been permitted to return to its normal position. Thus unintended repeat operations of the actuator type bar are prevented.

What is claimed is:

1. Ina power driven typewriter, an array of type actions and operating means therefor comprising, a rotating cylinder, comb-slotted mountingmeansfor pivotally movable parts, rocker actuators in said mounting means at opposite sides of the cylinder, a line of sub-levers in spaced arrangement on the mounting means and connected for operation by the actuators, means connecting the sub-levers to the type actions respectively, a single lobe cam rotatably mounted on each actuator and adapted to be engaged with and rotated by said cylinder, means for normal- 1y 'preventing rotation of the cam and insuring its complete rotation when desired, saidmeans comprising a pivot, a latch on said pivot, an operating linger on said pivot, anda spring between the latch and the ngernormally tending to bias the latch into effective position to hold s the cam against rotation and to bias the iinger into position to rotate the cam initially into engagement with said cylinder when the latch is released and complete the rotation of the cam to latching position at the end of its engagement with said cylinder, and key operated means adapted to release the latch and effective to transmit pressure by said spring to said operating finger.

2. In a power driven typewriter, an arrayvof type actions and operaitng means therefor comprising, a rotating cylinder, mounting means, actuators on said mounting means, type bars, connections from said type bars to said actuators, a single lobe cam rotatably mounted on each actuator and adapted to be engaged with and rotated by said cylinder, means for normally preventing rotation of the cam and insuring its complete rotation when desired, said means comprising a pivot, a latch on said pivot, an operating finger on said pivot, and a spring between the latch and the iinger normally tending to bias the latch into eiective position to hold the cam against rotation and to bias the ringer into position to rotate the cam minauy into engagement with said cylinder when the latch is released and complete the rotation of' the cam to latching position at the end of its engagement with said cylinder, and key-operated means adapted to release the latch and eifective to transmit pressure by said spring to said operating linger. I

RUSSELL `G. THOMPSON.- l y celeration of movement of the type bar to the 

